MOSCOW, March 25 (UPI) — The crew of a plane that made a belly landing while approaching Moscow used a pocket GPS device instead of the airport’s navigation system, an official said.

The plane, a Tu-204 operated by the state-controlled Aviastar, was returning from a flight to Egypt Monday when it made an emergency landing, crashing in the woods near Moscow’s Domodedovo International Airport during heavy fog.

All eight crew members were injured and the aircraft was heavily damaged.

The plane, a modern Russian airliner, had carried more than 200 passengers to Egypt but only the crew was aboard when it crash-landed.

An official told a Russian business daily investigators are focusing on the navigation method used by the crew, the Russian news agency RIA-Novosti reported Thursday.

The business daily Kommersant said Domodedovo is equipped with a special navigation system that allows a plane to land during the most difficult weather conditions.

The crew of the Tu-204 failed to notify air traffic control, as required, that they were switching to manual guidance for their landing, the official said.